„Check Engine“ indicator 1987

[seriously111]

My red check engine indicator on dashboard has lit up.
(Not the active control panel)
In the many years I’ve had the 1987 535i - it’s a first.

I’m not sure what it indicates tho? The car starts without problems and runs fine (perhaps a bit sluggish)
Does anyone know what triggers this light?
I believe this is connected to the motronic (basic)?

I’m thinking there might be a very slight vacuum leak somewhere.
Could that be the culprit?

The light only comes on after the car is driven - not when it starts up and idles.

Thankful for ideas. I’m looking at the motronic tech article but i would love to hear if you guys agree this is the best place to start.
Cheers!

[Aldo525]

My red check engine indicator on dashboard has lit up.
(Not the active control panel)
In the many years I’ve had the 1987 535i - it’s a first.

I’m not sure what it indicates tho? The car starts without problems and runs fine (perhaps a bit sluggish)
Does anyone know what triggers this light?
I believe this is connected to the motronic (basic)?

I’m thinking there might be a very slight vacuum leak somewhere.
Could that be the culprit?

The light only comes on after the car is driven - not when it starts up and idles.

Thankful for ideas. I’m looking at the motronic tech article but i would love to hear if you guys agree this is the best place to start.
Cheers!

Not sure because my cars are Euro, I mean, there is no "Check Engine Light" in the Euro instruments cluster.....just "CHECK" in the middle related to other failures, but look at this thread...

viewtopic.php?t=151812

[vinceg101]

These cars do not have a "CEL". Can you snap a pic of the light?

[seriously111]

Trying to post an image here… see if that works?

I think the later e28‘s (mine is built 9/87) had a very rudimentary light connected -I believe- to motronic? The light is just to the right of the High Beam indicator. I don’t think there is a stomp test like in later motronic. My light does not flash. It comes on only once the car is driven. I’m wondering if it might be caused by a vacuum leak (and if I’m starting on the right path anyway:)

https://share.icloud.com/photos/064LJHL ... xzZiGNjQuw

[Aldo525]

Trying to post an image here… see if that works?

I think the later e28‘s (mine is built 9/87) had a very rudimentary light connected -I believe- to motronic? The light is just to the right of the High Beam indicator. I don’t think there is a stomp test like in later motronic. My light does not flash. It comes on only once the car is driven. I’m wondering if it might be caused by a vacuum leak (and if I’m starting on the right path anyway:)

https://share.icloud.com/photos/064LJHL ... xzZiGNjQuw

A very old thread here, posted by Turbodan 15 years ago, related to "Check Engine" lights on e28 528 and why that light comes on.

Post by turbodan » Jan 18, 2008 12:25 PM
The 88 528 has four self diagnostic/emergency running codes. One is for the air flow meter potentiometer, one is for the intake air temp sensor, one is for the coolant temp sensor and the other is for the oxygen sensor.

Most common would be the oxygen sensor.

[seriously111]

I saw that post as well -
Thing is, Bentley says those cars were on Motronic 1.1 which had rudimentary diagnostics as well. Bentley shows a flashing sequence for failure codes also.

My 535i is on ‚basic‘ motronic. Ie no ‚check engine‘ diagnostic flashing sequence. Some cars even have no check engine light at all:) This car just has a solid warning that shows up not at start - but only whenever the car drives off.

My o2 sensor is about 2 years old. So, it might well be time for a new one. I guess I’ll start there…
Could anything other than motronic trigger a solid engine check light on an e28?

[Mike W.]

Technically 535s had Motronic 1.0a, which is adaptive and slightly more sophisticated than 1.0. But still no diagnostic capability.

Much to my surprise, right clicking and open in a new tab did open the iphoto site and your picture. As far as the light, yes it says check engine, obviously, but another surprise to me. My best guess is a lamp is plugged in there that shouldn't be. I'd take the cluster out and unplug that light which is probably a push in. And or make note of the wire colors and trace it out on the ETM.

[Aldo525]

Technically 535s had Motronic 1.0a, which is adaptive and slightly more sophisticated than 1.0. But still no diagnostic capability.

Much to my surprise, right clicking and open in a new tab did open the iphoto site and your picture. As far as the light, yes it says check engine, obviously, but another surprise to me. My best guess is a lamp is plugged in there that shouldn't be. I'd take the cluster out and unplug that light which is probably a push in. And or make note of the wire colors and trace it out on the ETM.

Checked my spare part Cluster, there are three "push in" possibilities: left first is "green double direction" for the towing/trailer hitch, then the mentioned "Check Engine" and to the right, "Anti Lock or ABS"......the cluster come with all the connectors and the push in type comes in the "Anti Lock" light with two wires: Green/White and Gray, so I suppose those colors are Anti Lock Light.

[seriously111]

Hm. So are you thinking it could be brake electrics related?
I did just redo brakes and have one unhooked brake sensor
I’m hesitant to just pull a light this early in the process of trying to figure stuff out…

I’ll leave that to the moment of teary-eyed defeat and a cold bottle of solace..

Good point re motronic 1.0a

[Mike W.]

I can't read it, but any chance the segment next to the CE light is ABS? Do you have an ABS light illuminated in the cluster? If not it sure looks like it's ABS and someone was in there and put it back in the wrong spot. Bizarre, but it would seem to be an easy fix.

[Aldo525]

Technically 535s had Motronic 1.0a, which is adaptive and slightly more sophisticated than 1.0. But still no diagnostic capability.

Much to my surprise, right clicking and open in a new tab did open the iphoto site and your picture. As far as the light, yes it says check engine, obviously, but another surprise to me. My best guess is a lamp is plugged in there that shouldn't be. I'd take the cluster out and unplug that light which is probably a push in. And or make note of the wire colors and trace it out on the ETM.

Checked my spare part Cluster, there are three "push in" possibilities: left first is "green double direction" for the towing/trailer hitch, then the mentioned "Check Engine" and to the right, "Anti Lock or ABS"......the cluster come with all the connectors and the push in type comes in the "Anti Lock" light with two wires: Green/White and Gray, so I suppose those colors are Anti Lock Light.

Looking e28Goodies, there are very good Electrical Diagrams....so I made a mistake in my previous post and checked my old "for parts" cluster was coming from a 88' e28 528e.....so:

ABS light is two wires: GY/RD + GN; grey/red + Green



Check Engine light is two wires: GN/WT + GR; Green/White + Grey

[/img]

The only way to know the true is removing the cluster and see what wires colors are there.....BTW, some others say "only 87/88 528e have Check Engine Light"....that's true, this light is not present at 535i according all diagrams at e28 Goodies.

[turbodan]

There is no check engine light functionality with the 059 DME in the e28 535i. There could be a "check engine" spot on the warning lamp lens and there could be a bulb erroneously plugged into it.

[seriously111]

I know my cluster is original and that it has not been removed in the 12 years I’ve had the car. The light is definitely there and factory original. It has also worked perfectly fine until now. Even now, it doesn’t light up when the car is first started, but only goes on after it is driven.
This means, it is likely being triggered by something and not a constant short etc. I think the CE light is connected to the motronic 1.0a. The ECU was tested 2 years (about 9k miles) ago and is likely working.

What did early motronics tie into? AFM? TPS sensor? Injectors?
The car does seem to be running rich so maybe it’s injector related but I’d love to know how the motronic worked before taking things apart.

There are a couple of Bosch motronic books out there. Any suggestions which one would be best for my 1.0a system?

.

[Aldo525]

My modest suggestion would be to take out the cluster, see the colors of the cables of that light and go from there... it would be easier to contribute to the solution or discover what the problem could be in a light that apparently should not have that model... ..it is not difficult to remove it and it would be very useful

[Mike W.]

I know my cluster is original and that it has not been removed in the 12 years I’ve had the car. The light is definitely there and factory original. It has also worked perfectly fine until now. Even now, it doesn’t light up when the car is first started, but only goes on after it is driven.

Which sounds like an ABS condition. You said, earlier.

I did just redo brakes and have one unhooked brake sensor

Was it the wear sensor or the ABS sensor that is unplugged? If you never had an ABS error before, you could have had it 12 years and never known it was in the wrong spot.

[seriously111]

It was just the wear sensor.
I really doubt this has anything to do with the brakes. They are new and functional.
I wish i knew what triggers this CE light. (And yes, my 1987 535i has one. Always has - its not a mirage. Motronic 1.0a)

Heres a picture of my dash at #2 position. You can see the CE light on left - far away from brake lights.

https://share.icloud.com/photos/04e6l95 ... XfdaljhC5A

[Aldo525]

Heres a picture of my dash at #2 position. You can see the CE light on left - far away from brake lights.

https://share.icloud.com/photos/04e6l95 ... XfdaljhC5A

Yes...it is far away from Brake lights but the point is that light is not a "fixed" bulb like "Battery" or "High Beam" which are on the printed circuit of the cluster....is just a socket with a bulb you can move and place in three different places of the (rear side) cluster....so, maybe that socket was bad relocated before you bought the car.

Does the Anti-Lock light come on when the Ignition is On (Pos2)???....should be on like "Battery" and the others

These are the three possible position for the socket: (left to right) Anti-Lock, Check Engine, Hitch/Towing.


This kind of socket

[jdb]

There is no check engine light functionality with the 059 DME in the e28 535i. There could be a "check engine" spot on the warning lamp lens and there could be a bulb erroneously plugged into it.

Further note about check engine light operation:
It would come on when the key is in the ON position before starting,This shows it is functioning.
Then after engine is running the light goes out, this indicates system check successful.
This started with Motronic 1.3

Jeff

[seriously111]

That is what happens....It goes on. Goes off upon start....but then it starts back up as soon as the car moves at a certain speed.
I've had the car myself for 12 years. It's never happened before.
I've looked through the service books (yes, i have them all) and there is no indication of prior work on dashboard etc.

i understand that very few e28's had that light. Mostly, it seems to have been 528e's. However, i am very certain that my 535i dashboard is original. It has worked perfectly and only now has started showing this fault. In general, the electrics have been rock solid with the exception of some understandable ground issues showing up after 30+ years.

Been looking at the Motronic literature but the book i have on Bosch Fuel Injection doesn't discuss that warning light setup.

[seriously111]

i have 15pin Motronic 1.1 - possibly 1.0a. No diagnostics (pedal check etc.)

[Zeta]

Please, for the sake of everyone’s sanity, can you just take out the cluster and see what wire colors are there, and whether there is actually a bulb behind the ABS light? I don’t think you’re going to receive a satisfying answer until you verify that. As Aldo pointed out, the ABS light should have been on in the picture you sent with the key in position 2, so the bulb being in the wrong place is still a very compelling possibility.

[Blue Shadow]

Fire up the ride go out onto a safe chunk of roadway and drive at 21 miles per hour.

Now jump on the brakes as hard as you can.

Did the antilock operate properly?

Yes: may not be the abs light in wrong spot
No: your abs light is in the wrong spot.

[Blue Shadow]

Need to know if the and light comes on when you are in the starting procedures and then goes off when the car starts, or when the throttle is blipped for those cars with lower voltage right after startup. Abs needs good running voltage on startup for the diagnostics.

So does the abs light come on during startup procedures?

[Mike W.]

Please, for the sake of everyone’s sanity, can you just take out the cluster and see what wire colors are there, and whether there is actually a bulb behind the ABS light? I don’t think you’re going to receive a satisfying answer until you verify that. As Aldo pointed out, the ABS light should have been on in the picture you sent with the key in position 2, so the bulb being in the wrong place is still a very compelling possibility.

Fire up the ride go out onto a safe chunk of roadway and drive at 21 miles per hour.

Now jump on the brakes as hard as you can.

Did the antilock operate properly?

Yes: may not be the abs light in wrong spot
No: your abs light is in the wrong spot.

While asking a question, OP seems convinced Motronic 1.0a has diagnostic capabilities. Regardless of what everyone else is telling him. He apparently knows and we don't. We're all a bunch of idiots.

[Blue Shadow]

I read it as he is not comfortable or doesn't know how to remove the gauge cluster.

Maybe he doesn't have a small screwdriver for those two screws up top or doesn't know they go in from below, pointing up. Or maybe he doesn't know the cluster will come out with the steering wheel in place but pulled back as far as it goes. Could be he can remove the white, blue and yellow multi-connectors cause the locking tab won't release.

Hell all that and I'd got check abs on a deserted chunk of roadway to verify its operation. I do that once a month anyway just for my own check, no relying on just the light to indicate malfunction. Fun when done on a street covered in wet leaves. The abs gets really busy.

I'm using an apple product so I cannot see the photos on i-Cloud he linked.

[Blue Shadow]

OK at the puter, now and can see the picture.

The position on the left that you have lit up is the "Startbereitschaft" light according to my German language 5-series Owner's Manual that covers the 518i, 520i, 525e, 525i, 528i, 535i, ///M535i and 524td. That means ready to start and is a lamp that is associated with the diesel E28s. I should be yellow-orange, not red and has no markings other than a dot matrix pattern, I believe. I'd have to look at my car to verify in the daylight as that is not a lit position on my car. You have US indicator labels in your car and I don't recall the color of that unused indicator position in the US cluster red would be logical.

Your ABS indicator lamp is in the wrong spot and until you go in and prove us wrong, you do not have a Check Engine light.

[Shawn D.]

Or maybe he doesn't know the cluster will come out with the steering wheel in place but pulled back as far as it goes.

And IME, turned slightly left, say, 11 o'clock.

[seriously111]

Ok guys - i do have a decent sense of humor about this stuff and dont take it personally when im shamed.
I took the time to undo the dashboard.

Lo and behold, the failing “check engine” (that is not a mirage. It exists!)
light is connected to Green / grey&red wires. The “antilock” indicator is connected to Grey/green white. Per Aldo’s post that would seem the ABS and CE lights are switched and must have been so for at least 12 years since ive had the car.

I will solve what appears to be an ABS situation?

Sorry about this silly way of posting things. I cant seem to insert pictures directly here. Trying it a different way.

https://pin.it/2aTBZRp

Thank you - all of you- for taking the time to look at my post.
I really do appreciate it.

[Aldo525]

Switched bulbs is good news....It is more easy to solve an ABS issue instead of a CE light in a car that's not supposed to have that light. But why that cables for CE is in your cluster??.....maybe only BMW Germany knows. (my best idea is that at the end of the production of the e28 (87/88) maybe the factory used common wiring in those models, even if that CE light was not used.)

Re the ABS, that system have a Control Unit, two relays and the sensor at the wheels....maybe one of that sensors are bad. There are a lot of Post here covering all the ABS problems.